[dkimball]

It is true that small differences can mean large conflicts, but I think Catholicism and Eastern Orthodoxy is a better illustration of this. The only doctrine that the two denominations disagreed on was the exact way in which the Pope is higher-ranked than the other metropolitan bishops; this plus language barriers and differences in cultural atmosphere produced something like 1500 years of mutual hostility which were only ended by John Paul II.

However, we can sometimes mistake _subtle_ differences for _small_ ones; but just as there's a substantial difference between the Mac OS and Windows, there's a substantial difference between Catholicism and Calvinism (which was the most successful form of Protestantism) -- the difference between God seeing that you went to Hell, and God sending you there. I could go into much greater detail (I count nine paragraphs in how I'd previously structured this comment), but that's the nutshell of the nutshell.

[jacquesm]

When looking at this from an atheists perspective it looks like very minor differences to me.

There's a joke about that, I looked it up:

I was walking across a bridge one day, and I saw a man standing on the edge, about to jump off. So I ran over and said “Stop! don’t do it!” “Why shouldn’t I?” he said. I said, “Well, there’s so much to live for!” He said, “Like what?”

I said, “Well, are you religious or atheist?” He said, “Religious.”

I said, “Me too! …Are you Christian or Buddhist?” He said, “Christian.”

I said, “Me too! …Are you Catholic or Protestant?” He said, “Protestant.”

I said, “Me too! …Are you Episcopalian or Baptist?” He said, “Baptist!”

I said, “Wow! Me too!…Are you Baptist church of God or Baptist church of the Lord?” He said, “Baptist church of God!”

I said, “Me too! Are you original Baptist church of God, or are you reformed Baptist church of God?” He said, “Reformed Baptist church of God!”

I said, “Me too! Are you reformed Baptist church of God, reformation of 1879, or reformed Baptist church of God, reformation of 1915?”

He said, “Reformed Baptist church of God, reformation of 1915!”

I said, “Die, heretic scum” and pushed him off.. — Emo Phillips

[dkimball]

@jacquesm: At least from my perspective, "God wants everyone to go to Heaven" and "God wants some people to go to Hell" are further apart than "God wants everyone to go to Heaven" and "there is no God, and the universe developed through chance and emergent patterns."

Calvinism had _huge_ practical consequences -- in social policy, it's the difference between ensuring that the poor are fed and sheltered, and kicking them into the street; and you can only imagine what it meant for the laws of war...

Edit: And the joke you mention is only too recognizable, but it's more like the Catholicism-and-Orthodoxy situation, where it's a matter of tribal loyalties more than views of the world...